Gas lift plungers are employed to facilitate removal of gas from wells, addressing challenges incurred by “liquid loading.” In general, a well may produce liquid and gaseous elements. When gas flow rates are high, the gas carries the liquid out of the well as the gas rises. However, as well pressure decreases, the flowrate of the gas decreases to a point below which the gas fails to carry the heavier liquids to the surface. The liquids thus fall back to the bottom of the well, exerting back pressure on the formation, and thereby loading the well.
Plungers alleviate such loading by assisting in removing liquid and gas from the well, e.g., in situations where the ratio of liquid to gas is high. In operation, the plunger descends to the bottom of the well, where the loading fluid is picked up by the plunger and is brought to the surface as the plunger ascends in the well. The plunger may also keep the production tubing free of paraffin, salt, or scale build-up.
During the plunger's descent to the bottom of the well (e.g., to a bumper assembly at the bottom of the production tubing), a bypass valve of the plunger is generally maintained in an open position, allowing the plunger to descend through the column of gas and liquids in the tubing. The plunger thus moves toward the bottom, sinking past liquid accumulations, etc. Once the plunger reaches the bottom of the well, the bypass valve is closed. The outer diameter of the plunger may seal with the production tubing, and thus, with the bypass valve closed, pressure below the plunger may serve to push the plunger upwards. As the plunger moves upwards, it clears the production tubing of liquid, allowing the gas to be produced.